Many present-day oil and gas exploration assemblies include equipment that is transported to the well head or drilling site. This equipment can include a blowout preventer, lubricator pipe, stripper assembly, and/or an injector head. A blowout preventer is sometimes called a “Christmas Tree,” and an injector head is sometimes called a “Crow's Nest.” Other equipment and derrick assemblies may also be assembled at the well head or drilling site, but the assembly process is usually conducted by having each piece of equipment lifted over other equipment by a crane prior to making the proper connections and attachments. This assembly process is very time consuming and labor intensive.
Single pivot oil derrick assemblies are shown in U.S. Pat. Nos. 6,003,598; 5,842,530; 4,290,495; 3,942,593; 3,136,394; 2,993,570, 2,829,741, 2,617,500 and 2,300,763. These assemblies erect the derrick structure to a vertical position using a single pivot point transport system. Single pivot transport assemblies require that the pivot point be extended to an end of the transport bed trailer, which increases the instability of the assembly apparatus during vertical alignment of the derrick assembly. These single pivot transport assemblies also reduce the ability to vertically aligned pre-assembled equipment, which must be assembled separately before or after the derrick assembly is raised to its vertical position. The pivot point being aligned with the end of the bed trailer also reduces the flexibility of the assembly structure by requiring that the end of the trailer be aligned with the well head at the drilling site. There is a need for a more stable vertical lift structure that raises pre-assembled equipment with increased flexibility in the positioning in relation to the well head location.
Some equipment assemblies are transported to the well head or drilling site on a flat-bed trailer, and vertically aligned using one or more hydraulic lift pistons or other lift devices. Such an assembly is shown in U.S. Patent Publication No. US 2008/00669968 for slant drilling, US 2007/0209791, US 2007/0125551, US 2006/0260844 (platform raised), and US 2003/0098150, as well as the assemblies shown in U.S. Pat. Nos. 7,357,616; 7,308,953; 7,306,055; 7,191,839; 7,111,689; 6,973,979; and 6,860,337.
These lift assemblies, however, often use the end of the trailer assembly as the pivot point for vertically raising the equipment, which increases the instability of the system during the vertical alignment process. Further, these lift assemblies often use a single pivot point for the vertical alignment process, which does not allow for increased flexibility for the positioning relative to the well head at the drilling site. Moreover, the lift assemblies do not appear to vertically align pre-assembled blowout preventers with other heavy equipment, which is quite difficult to vertically align based on the significant weight and elevated centers of gravity. There is a need for a more stable vertical lift structure that raises pre-assembled equipment with increased flexibility in the positioning in relation to the well head location.